Mathworks' RF Toolbox includes signal integrity capability

Providing a signal-integrity analysis capability for broadband backplanes and PCB traces, The Mathworks is rolling out the RF Toolbox 2, which adds time-domain capabilities to this Matlab add-on package. As a result, the company said, engineers can significantly reduce the time needed to develop I/O circuitry for high-speed digital systems.

The RF Toolbox extends Matlab with functions and a graphical user interface for debugging, modelling, analysing, and visualizing networks of RF components. It outputs rectangular, polar, and Smith charts. The original RF Toolbox 1, introduced in 2004, is used for wireless communications design

RF Toolbox 1 works only in the frequency domain, noted Colin Warwick, technical marketing manager for the RF Toolkit. "Signal integrity engineers couldn't make much use of version 1, because it didn't support broadband time domain functions," he said. "We've added those features to version 2, opening it up to the signal integrity community."

In high-speed digital systems, the communication channels between ICs are running at GHz frequencies, Warwick noted. "It turns out it's no longer a digital problem, it's an RF analogue problem, because people are building mini-communications systems on every pin of every high-speed IC," he said. "Those I/O drivers are trying to communicate at RF frequencies."

To assist with this kind of modelling, RF Toolbox 2 can read in frequency-domain data and convert it to rational function models, which provide a compact modelling format in the time domain. This model can be simulated in The Mathwork's Simulink product. It can also be exported to the Verilog-A format for use in EDA tools for IC design.

RF Toolbox 2 claims to eliminate the need for manually building transmission-line models from measured data to test I/O circuit designs. Instead, engineers can model transmission lines as rational functions, which The Mathworks claims are faster and more accurate than traditional approaches like Inverse Fast Fourier Transforms.

"We can bridge the gap between vector network analysers that work in the frequency domain, and Simulink and EDA tools that want to work in the time domain," Warwick said. "We can take thousands of frequency domain data points and boil them down to a handful of time domain parameters."

In this way, said Warwick, signal integrity engineers can build and simulate impairment models that illustrate signal-integrity problems. They can then create mitigation algorithms, adding such capabilities as pre-emphasis filters or decision feedback equalisers.

Warwick also noted that designers could use The Mathworks' recently-announced Simulink HDL Coder to generate VHDL or Verilog for a mitigating algorithm for an equaliser or a filter.

The RF Toolbox 2 is available now on Windows, Unix, Linux, and Macintosh platforms starting at $1,000.